Currently it appears that when defining a subscription the return type annotation must be set to typing.AsyncGenerator[str, None], like so:

@strawberry.type
class Subscription:
    @strawberry.subscription
    async def time(self, info) -> typing.AsyncGenerator[str, None]:
        ...

Do we need to use typing.AsyncGenerator as the return type for subscription definitions? I'm not sure that I love that dev experience. Would it be bad practice to use raw types as the return type? Something like:

@strawberry.subscription
async def time(self, info) -> str:
    ...

Or maybe a we could use a custom return type for subscriptions:

@strawberry.subscription
async def time(self, info) -> strawberry.subscription_result(str):
    ...